From Wikipedia, the free encyclopedia

Overall equipment effectiveness (OEE) is a
hierarchy of metrics which focus on how effectively a manufacturing
operation is utilized. The results are stated in a generic form
which allows comparison between manufacturing units in differing
industries.

The
two top-level metrics

Overall equipment effectiveness (OEE) and total
effective equipment performance (TEEP) are two closely
related measurements that report the overall utilization of
facilities, time and material for manufacturing operations. These
top view metrics directly indicate the gap between actual and ideal
performance.

Overall equipment effectiveness quantifies how well a
manufacturing unit performs relative to its designed capacity,
during the periods when it is scheduled to run.

The
four underlying metrics

In addition to the above measures, there are four underlying
metrics that provide understanding as to why and where the OEE and
TEEP performance gaps exist.

The measurements are described below:

Loading: The portion of the TEEP Metric that
represents the percentage of total calendar time that is actually
scheduled for operation.

Availability: The portion of the OEE Metric
represents the percentage of scheduled time that the operation is
available to operate. Often referred to as Uptime.

Performance: The portion of the OEE Metric
represents the speed at which the Work Center runs as a percentage
of its designed speed.

Quality: The portion of the OEE Metric
represents the Good Units produced as a percentage of the Total
Units Started. Commonly referred to as First Pass Yield.

Calculations for OEE and
TEEP

What follows is a detailed presentation of each of the six OEE /
TEEP Metrics and examples of how to perform calculations. The
calculations are not particularly complicated, but care must be
taken as to standards that are used as the basis. Additionally,
these calculations are valid at the work center or part number
level but become more complicated if rolling up to aggregate
levels.

Advertisements

Overall equipment
effectiveness

OEE breaks the performance of a manufacturing unit into three
separate but measurable components: Availability, Performance, and
Quality. Each component points to an aspect of the process that can
be targeted for improvement. OEE may be applied to any individual
Work Center, or rolled up to Department or Plant levels. This tool
also allows for drilling down for very specific analysis, such as a
particular Part Number, Shift, or any of several other parameters.
It is unlikely that any manufacturing process can run at 100% OEE.
Many manufacturers benchmark their industry to set a challenging
target, 85% is not uncommon.

Calculation: OEE = Availability x Performance x
Quality

Example:

A given Work Center experiences...

Availability of 86.7%

The Work Center Performance is 93.0%.

Work Center Quality is 95.0%.

OEE = 86.7% Availability x 93.0% Performance x 95.0% Quality =
76.6%

Total effective
equipment performance

Where OEE measures effectiveness based on scheduled hours, TEEP
measures effectiveness against calendar hours, i.e.: 24 hours per
day, 365 days per year.

Loading

The Loading portion of the TEEP Metric represents the percentage
of time that an operation is scheduled to operate compared to the
total Calendar Time that is available. The Loading Metric is a pure
measurement of Schedule Effectiveness and is designed to exclude
the effects how well that operation may perform.

Calculation: Loading = Scheduled Time / Calendar
Time

Example:

A given Work Center is scheduled to run 5 Days per Week, 24
Hours per Day.

For a given week, the Total Calendar Time is 7 Days at 24
Hours.

Loading = (5 days x 24 hours) / (7 days x 24 hours) = 71.4%

Availability

The Availability portion of the OEE Metric represents the
percentage of scheduled time that the operation is available to
operate. The Availability Metric is a pure measurement of Uptime
that is designed to exclude the effects of Quality, Performance,
and Scheduled Downtime Events.

Calculation: Availability = Available Time / Scheduled
Time

Example:

A given Work Center is scheduled to run for an 8 hour (480
minute) shift.

The normal shift includes a scheduled 30 minute break when the
Work Center is expected to be down.

Performance

The Performance portion of the OEE Metric represents the speed
at which the Work Center runs as a percentage of its designed
speed. The Performance Metric is a pure measurement of speed that
is designed to exclude the effects of Quality and Availability.

The Standard Rate for the part being produced is 40 Units/Hour
or 1.5 Minutes/Unit

The Work Center produces 242 Total Units during the shift. Note:
The basis is Total Units, not Good Units. The Performance metric
does not penalize for Quality.

Time to Produce Parts = 242 Units * 1.5 Minutes/Unit = 363
Minutes

Performance = 363 Minutes / 390 Minutes = 93.0%

Quality

The Quality portion of the OEE Metric represents the Good Units
produced as a percentage of the Total Units Started. The Quality
Metric is a pure measurement of Process Yield that is designed to
exclude the effects of Availability and Performance.